Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 30, 2018
Payables and Accruals [Abstract]
Direct costs of sales	$ 5,363	$ 4,450
Accrued corporate cost expenses	1,292	3,167
Asset retirement obligations	559	571
Interest payable - cash	46	102
Other creditors	5,199	6,064
Accrued expenses, net	$ 12,459	$ 14,354